1. Field of the invention
The present invention relates to a tool handle connection system and apparatus. More particularly, the present invention relates to such an apparatus which connects a tool handle to a broom head or other tool head, such that the tool handle is fixed axially and rotationally in relation to the tool head.
2. Description of the Relevant Art
Some types of tool handle connection systems and apparatus are known for fixedly attaching a tool handle to a tool head. Some of the known systems include a tool handle with threads formed on the exterior surface of one end, which end is screwed into a corresponding internally threaded aperture in a tool head. Some other known systems include a stud fixedly attached onto a tool head, which is screwed into a corresponding internally threaded aperture within a tool handle. This invention focuses on systems of the first type, since systems of the first type are much more common, and systems of the second type are difficult to use with metal tool handles.
Although providing a simple connection system, tool handles attached with systems of the first type have several shortcomings. These systems have a tendency to fail within a relatively short time. With such systems, the tool handle tends to rotationally unscrew with use. When the tool handle becomes partially unscrewed, the stress on the connection threads greatly increases. Typically, such threads shear off from the handle, requiring handle replacement, or shear off from the tool head, making the tool inoperable for its intended use.
On many such systems used, for example with conventional push brooms, the tool head includes an alternate threaded aperture. The additional threaded aperture can prolong tool life when the primary threaded aperture becomes degraded. Such a design, however, weakens the structural integrity of the tool head and often results in tool heads breaking with use.
Another example of a known tool handle connection system and apparatus is U.S. Pat. No. 4,285,096, issued in 1981 to Swaim, and entitled xe2x80x9cINDESTRUCTIBLE HANDLE FOR MOP OR BROOM AND METHOD OF MAKING SAME.xe2x80x9d The Swaim patent discloses a handle which is constructed so that it either may be placed on a mop head, with a female thread formed in a plug thereof screwing onto a stud which is fixedly attached to the mop head, or may be screwed into the internally threaded aperture of a standard push broom head. The handle disclosed by Swaim includes a tubular steel handle member, with a plastic or vinyl sleeve on the outside of the steel handle. A solid steel plug is disposed in an end of the tubular member, and a part of the plug extends outwardly from the end of the steel tube, and has male threads formed on the exterior side surface thereof. The steel tube is crimped in place around the plug, and is then optionally spot welded to the plug for extra help.
Although providing a handle connection apparatus which may be attached using the first connection system, the Swaim patent fails to address problems created by tool handles partially unscrewing with use. Additionally, the primary crimping attachment method disclosed by Swaim allows for the tubing to unscrew from the plug, since the tubular handle member is crimped onto a threaded surface of the plug.
In order to compensate for the handle unscrewing from the plug, Swaim includes the option of spot welding the handle to the plug. Crimping as well as spot welding creates a connection apparatus which is not simple nor easy to use. Spot welding still does not address the problem of a tool handle partially unscrewing from a tool head with use.
Although making an improvement over the conventional systems and apparatus for connecting tool handles to tool heads, the Swaim disclosure doesn""t entirely fill the needs of the industry. A need still exists in the art for a tool handle connection system and apparatus which is simple and easy to manufacture and use, highly durable, and which axially and rotationally fixes a tool handle to a tool head.
The present invention has been developed to overcome the foregoing limitations and disadvantages of known tube tool handle connection systems and apparatus, and to generally fulfill a need in the art for a tool handle connection system and apparatus which is simple and easy to manufacture and use, highly durable, and which axially and rotationally fixes the tool handle to the tool head.
According to the invention there is provided a tool handle including an elongate metal tube, and a connection member. The connection member has one attachment end thereof fitted in an engagement end of the metal tube, and an opposite, threaded end, axially projecting from the metal tube and connection member assembly. The metal tube is crimped around the attachment end of the connection member, and the threaded end of the connection member includes self-tapping screw threads. Self-tapping screw threads are desirable since they are difficult to unscrew compared with large threads found in some conventional tool attachment systems.
In order to prevent rotation of the tool handle relative to the connection member, the connection member includes at least one, and preferably two, flat regions engaged by a crimped portion of the end of the elongate metal tube.
The connection member preferably includes a means for reinforcing axial retention of the metal tube. Such means may include an interference fit between the connection member and the metal tube, scored surface areas on the connection member, or annular rings on the connection member.
It is further preferable that the connection member includes a stopper means for limiting insertion of the attachment end into the metal tube. It is further preferable, that the cross-sectional area of the attachment end of the connection member tapers down from a point intermediate along the longitudinal axis of the connection member, to a point at the end of the attachment end to act as a stopper means. Alternatively, such insertion may be limited by an annular flange having an outer diameter larger than the outer diameter of the elongate tube, located at an intermediate point along the connection member.
In an alternative configuration of the invention, the tool handle further includes a plastic insert band fixedly crimped within the engagement end of the elongate tube. Additionally, the attachment end of the connection member includes a standard screw head having flat regions peripherally therearound, which are engaged by crimped portions of the engagement end of the elongate metal tube. The band reinforces attachment of the connection member to the metal tube, and reduces the potential of wobble between the connection member and the metal tube.
It is an object of the present invention to provide a tool handle connection system and apparatus which axially and rotationally fixes a tool handle to a tool head.
Another object of the present invention is to provide a tool handle connection system which is highly durable, as well as simple and easy to manufacture and use.
For a more complete understanding of the present invention, the reader is referred to the following detailed description section, which should be read in conjunction with the accompanying drawings. Throughout the following detailed description and in the drawings, like numbers refer to like parts.